Wireless subscribers expect access to TCP/IP (Transmission Control Protocol/Internet Protocol)-based applications from their mobile phones. However, these applications must be adapted to overcome resource limitations and security restrictions typical to wireless networks in order to make them viable. For example, a server in the network may not be permitted to establish a connection to a client on a mobile handset to limit unsolicited data traffic. Also, the wireless network may assign a different IP address to a mobile device for different data sessions, making it unfeasible for a network server to initiate a connection.
The number of IP addresses available in the network to be allocated to a mobile device is generally less than the total number of mobile customers. As a result, the wireless network may not allocate a dedicated IP address to a mobile device. The address allocated to the mobile device may change from a data session to another data session. This imposes a technical challenge for a messaging server to reach a mobile device using its IP address.
During a TCP/IP-based application session, the data exchange between a mobile application client operating on a mobile device and an associated server in a wireless network may include bursts of high activity with large idle periods. This bursty nature may be seen in IP messaging services, such as text and picture message exchanges. After the initial exchanges, either the client or the server could have data to exchange following an idle period where, unknown to the client or the server, the TCP connection may have been terminated somewhere along the wireless network.